gbeenway thomas



(No Model.)

E` C. G. THOMAS.

DREDGER.

Pai-,811888008 21, 1884.

UNITED STATES PATENT Orrrce.

E. GREENVAY THOMAS, OF LONDON, COUNTY OF MIDDLESEX, ENGLAND.

DREDGER.

'.2'IPE.LEFICATION forming part `0f Letters Patent No. 306,787, datedOctober 21, 1884.

Application filed April l, 1884. (No model.) Patented in England April23, 1883, No. 2,049.

To all whom, it may concern:

Be it known that I, EDWARD CRorr GREEN- WAY THOMAS, a subject of theQueen of Great Britain and Ireland, and a resident of the city ofLondon, in the county of Middlesex, in that part of Great Britain calledEngland, have invented a new and useful Dredging-Machine, (for which Ihave obtained a patent in Great Britain,No. 2,049,bearing date Apri] 28,1883,) of which the following is a specitication.

I construct a cigar-shaped body having a specific gravitya little inexcess of that of water, so that it will sink, but will lie on the bottom without much pressure. At one end of this cigar-shaped body I fixhelical blades, and I hold such body by a chain or rope attached theretoby a swivel, so as to leave the body free to revolve. On the body I fixspikes or sharp projections. Then such body is thrown into'a current ofwater, it sinks and lies lightly on the mud or sand at the bottom, andas it is held stationary by the rope or chain the current, acting on itshelical blades, causes the body to revolve, so that its spikes or sharpprojections, revolving, stir up the mud, sand, gravel, or othersedimentary deposit, which the current sweeps away.

The accompanying ,drawing shows an elevation of my automatic dredgeraccording to my invention.

A is the cigar-shaped body, which I prefer to construct of hollow metal.It is so constructed as to sink in water without pressing too heavily onthe mud or sand bottom B.

On the front part of the body A, I tix helical blades C, which may beeither continuous,

as shown in the drawing, or may be separate segments, like the bladesot' a screw -propeller.

On the bulge, or slightly in the rear of the largest periphery of thebody A, I affix sharp projections or spikes D, which may be plain s)ikes as shown or ma be shar) iroeetions l 7 l Y l l .l

of a form to suit the character of the material at the bottom B. Thenumber of such spikes varies in like manner with the character of suchmaterial.

The dredger being held by a rope `or chain attached to a swivel, E, in acurrent of water ilowing in the direction of the arrow F, the current,acting on the blades C, causes the body A to revolve, and the revolvingspikes D break up and agitate the mud, sand, or: other loose sedimentarymaterial at the bottom, so that the disturbed layer is washed away bythe current.

The dredccr, instead ot' bein@ siationar i may bc drawn along againstthe current, so

that it may revolve with increased force; orit may be revolved by beingtowed in still water.

Having thus described the nature of my invention and the manner of itsoperation, what I desire to claim and secure by Letters Patent isl. Anautomatic dredger composed of the cigar-shaped body A, having a specificgravity a little in excess of that of water, furnished with sharpprojections D, suitably formed and disposed for stirring up mud, gravel,or sand at the bottom ot' a stream of water, such body being providedwith helical blades C, and a swivel, E, so constructed and placed as tocause the body to revolve when placed at the bottom of a current ofwater and held or drawn against such current.

2. In a dredger, a revolving body actuated by the force of a current ofwater acting on blades or screws attached to such body, and armed withspikes or sharp projections for the purpose of breaking up and agitatingmud, sand, or other sedimentary materia-l, substantially as described.

3. In a dredger, the combination of the revolving body A, the blades C,and the spikes or sharp projections D, arranged and operatingsubstantially as described.

E. O. GREENE/'AY THOMAS.

IVi tnesses:

` J. PLAYs'rEn S'rnnDs,

RICHARD CASTLE,

Both of 37 6 Strand, London.

